Revert r160071 "Web Animations: Implement AnimationClock and fix start time of animations"

Source/core/animation/DocumentTimeline.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 36 matching lines @@
 // DocumentTimeline is constructed and owned by Document, and tied to its lifecycle.
 class DocumentTimeline : public RefCounted<DocumentTimeline> {
 
 public:
     static PassRefPtr<DocumentTimeline> create(Document*);
     void serviceAnimations(double);
     PassRefPtr<Player> play(TimedItem*);
     // Called from setReadyState() in Document.cpp to set m_zeroTimeAsPerfTime to
     // performance.timing.domInteractive.
     void setZeroTimeAsPerfTime(double);
-    double currentTime();
+    double currentTime() { return m_currentTime; }
     void pauseAnimationsForTesting(double);
     size_t numberOfActiveAnimationsForTesting() const;
     AnimationStack* animationStack(const Element* element) const
     {
         if (ActiveAnimations* animations = element->activeAnimations())
             return animations->defaultStack();
         return 0;
     }
     void addEventToDispatch(EventTarget* target, PassRefPtr<Event> event)
     {
         m_events.append(EventToDispatch(target, event));
     }
 
 private:
     DocumentTimeline(Document*);
     void dispatchEvents();
+    double m_currentTime;
     double m_zeroTimeAsPerfTime;
     Document* m_document;
     Vector<RefPtr<Player> > m_players;
 
     struct EventToDispatch {
         EventToDispatch(EventTarget* target, PassRefPtr<Event> event)
             : target(target)
             , event(event)
         {
         }
         RefPtr<EventTarget> target;
         RefPtr<Event> event;
     };
     Vector<EventToDispatch> m_events;
 };
 
 } // namespace
 
 #endif